I’ve seen this in a few places, and I haven’t been able to find anything to explain this:

悲劇の中に出でてる聖杖の賢者…その杖、我らを護る盾とならん！

This is an incantation that causes the units to not take any damage in the game that it’s from (here’s a link if it helps with anything: http://www.youtube.com/watch?v=wnr2tdX1AlM). Because of that I’ve translated it as:

“Wise man with the holy staff appearing in the midst of tragedy,thy staff shall be the shield that protects us!”

The problem is that according to everything I’ve found ならん comes from ならない, which would make it mean “doesn’t become the shield,” but that doesn’t make sense with the effect. And there’s a bunch of other incantations that use this ending in the same way.

The only thing I can think of is that it may be archaic based on the grammar of other incantations, but that still doesn’t tell me what it’s supposed to do.

Yes, it is said to be so since around the 10th century, I guess.But, as yangmuye-san said, they are not used in modern Japanese anymore.(And he is right. む is not a particle but a 助動詞[auxiliary verb].)

yangmuye wrote:Its a suffix like ず,れば,れる,etc. rather than a particle.It's called 助動詞 in 学校文法.

Ranja wrote:as yangmuye-san said, (...) む is not a particle but a 助動詞[auxiliary verb].

um...The question is rather complex.I said It's called 助動詞 in 学校文法, it does mean it's an auxiliary verb.Auxiliary verb is 補助動詞 in 学校文法. Anyway, knowing the category can't help you much.

Asevela wrote:I’ve got two more questions, then. Are けむ and らむ also pronounced けん and らん, and is む attached to the same form as ない? I don’t think I’ve seen it with anything besides なる and 一段 verbs, so I’m not sure.

It's seems that your questions are even beyond the scope of N1. (Though I'm not sure.)

大辞林 wrote:幸多からんことを祈る政治家たらんとする者はあらん限りの力まさに出発せんとする時

As I said, む is a suffix, so we can call the form it attached to the む form. In modern Japanese, it's generally the same as ず. In Old Japanese, it's even more complex.多からずんせずんあらずんOccasionally you can see it written む, which clearly shows that it's not negative.(There are also many people who wrongly write あらぬ限りの力.)